Centrifugal separator bowl



` Filed NOV. 5, 1941 H@ @zo June 19., 1945.

I [wm/.55.55 f

`Patented June 19, 1945 l 772,375,778... i y CENTRIFUGAL snranait'aiiowpff I u Hans olaf Lindgren, Appexviken; and. Hennef? Thylefors, Stockholm, Sweden, assignors to Th De `Laval Separator Company, New York, a corporation ol.' New "Jersey f- Application November 5, 194i, S riall 4 f In Sweden December] i I s claims.` (cifz -ez l This invention is drectedto an improvement in a centrifugal separator bowl, more particular# ly of the `type in which a sludge separated from theiliquid undergoing treatment is discharged from the periphery of the bowl.

if lnltreatinglliquids containing aj high percentage of sludge, it is customary to use centrifuge bowls which are provided with discharge openngswhich are opened periodically for the" discharge ofsludge accumulated in the sludge space.

Such discharge lopenings may either be opened at prede'termined intervals, or whenever the separated liquid becomes incompletely purified!l -The present invention relatesto the improvement in means for automatically opening such discharge openings whenever a given amount of solids has been deposited in the sludge space of thef bowl. i. f l

`A `preferred embodiment of `thetinvention is `shown in the accompanying drawing, in which the single" ligure is Vav vertical cross 'section through a centrifuge `bowl in accordance with l the present invention. In the centrifuge bowl shown in the gure,.the l walls ofthe bowl are lformed of a lower member I mounted upon a spindle 2, and an upper memf bert` 3V secured to the lower member by alock ring5f` Within the bowl so formed, `and closely adjacent the lowerwall Lisa `member 'I which iskeyedto the centrifuge bowl at 9 so asto be 30 `axially movable with respect thereto. `'l'his slide member 'I is adapted to make, in its upperposition, a liquid tight seal at Ill` `with the upper part -3iof the centrifuge bowl, while in its lower positionen annular discharge opening will be formed atl I0 between the slide member `I and the bowl wall 3; `Secured to `and supported by theslide member `1 in conventional manner are vmeans forming a central inlet channel` Il for `liquid to be purified, and a pile of separator` discs I3.

secondgroup of separator discs I4 are positioned justabove the slide member 1, and form with1 the` slide member a series of channels I5 l `leading, from the bowlproper through a passage, IIintothe chamber I9` formed between the-wall 45 When thecentrifuge is in operation,` aportion the iiquid to be Purified Wm be purified in that portion of the bowl space occupied b y the discs, I4; land thepuried liquid there separated l stricted discharge, openings o er `edgesofthe separating discs I3.

uid will be continuously supplied to thebowl in sufficient quantity to compensate for theliquid discharging through the `openings 2|. Since the liquid Lr'iassing` into thechambcrl 9 will have been purified, there is no danger that the discharge `openings `A2I may beblockedby sludge or other impuri'tiesgcarried bythe liquid. "i So longas' the chamber I9 'is lled with'liqiiid,

the 1upward force exerted byithe pressure oftheliquid ,chamber *I S'against the" slide `meinlnr Twill exceed the'A downwadf'forcfe exerted against this slide member by the` main body rof liquid in the' centrifuge bowl, -and the slide `member will consequently" assume *its upper `position Ii1n"\7vhi `;h` the annular discharge cpening I0 is closed. l? As sludge" accumulates inthe sludge space of the centrifugebowl, the level of accumulated sludge will "gradually move inwardly-until it reaches fthe radial level 'iridited lby the liieAl Alf` this level it willlbegin toclog the channels' I 5 formed between the discs I 4 and so`prevent the entry of liquid to theseparatingspace occupied by these discs; and thence'through the passage I1 to the chamber I9; Consequently,` as "liquid escapes from: the chamber` `I 9 @through` the"- discharge openings` 2 I :the pressure within l that chamber will be reduced and the slide" member 1' willbe forced downwardly by -th`e pressure `within the centrifuge "bowl proper. The downward movement ofthe" slide member `1 will open the 'ane nular discharge opening Ill through which ai por-'- tion of theaccumulatedvsludge will be discharged from the centrifuge bowl. l The level of sludge in the centrifuge bowl will thereby rece de from the level indicated by the line A, and `liquid will once more iiow through the channels I5 between the "discs'll'l,V andthen'ce `into the chamber` I9. As soon asthe'upward` forces exerted by the liquid Lw'itliintlfie chamber I9 exceedA the downwardfres'exertedfby the main body' of liquid inthe 'centrifuge bowLtheslidemember 'l'will ing -10'1y l l i' In accordance" with" the' present, invention, 'the fbemovedfupwardly tolclose the discharge"open-- extent of the annular discharge opening :Ill

formedby the `donmwardmovement of the slide Vmember AI *is so J controlledastoprevent all of the sludge? contained in 'thesludge space of` the fbowl "from" flowing "outbeforezk'the opening `is closed again: It tistherefore not necessary, in accordance with` the present inventiomfto' interrupt the.' supply `of fliquid'y to be separated.

will"flewthroughthe-Jpassage `Il into-the cham- 'Unless 'a v'ery coarse sludge `is containedginthe sludge space, it will be desirable, in accordance with the present invention, to further throttle the dischargeof sludge, when the annular discharge opening I is opened, by surrounding this discharge opening with a ring 25 containing a plurality of throttled openings 23. Both the discharge openirig-` the :oiehigs'are in line with openings 21 formed in the outer wall of the bowl.

It is, of course, also possible to arrange the ing III instead of outside. In either case, in order throttled openings 23 inside the annular open.-

that the opening shall have the desired effect; Y

the play between the slide viher'nber. 1:" andthe lxed wall 3 of the bowl must-be very small', so that only a very small part .of the sludge can be discharged from the bowl; In the structure shown a recess will be formed just: inside the,- throttled openings 23 when the slide vmember 1 passage I ,I to theichamber I9. ."rhis,` however.

is not particularly desirable, reiner-tr such liquid will not' be purified and sludge `will enter the chamil 10erv ISI,

. In accordance withthe-present invention, itis ytherefore preferred toprovide alseparate supply o f puried liquid for filling 'thechamber IS; and

thus holding the bowl closed while` thebowl is being nuca `with ,liquid ,tc be puricajsuch separate supply of liquid may be conveniently vadmittedfthrough `a channel 29 in the spindle 2 on the separatorv -bowll The channel @29 I' may come municate, in conventional manner, with alii/red stationary pipe;n the. connection being suitably packed so the liquid may be supplied throughthe channel 29 underA pressure;` .Liquid from the channel `29. Will-pass'to-jthe chamber rI9 through passageway 33` controlled by valve-3l, and channel 35.` Valve 3l is normally held against. its seat by" a springl 32, and .thus'closes communication between the channel 429 and the chamber ISwhen the slide member 1 is in its upper position. When the slide member 1, however, is in its lower position, ,valve 3I is opened. bythe head of screw 31, thus permitting liquid `under pressure to enter the ,chambery I9- frorn"the chjannelg29,4 solas to raise the slide 1 and close: the discharge open'- `If. the supply o-fli'quid 'under pressure to the channel 29 is maintained not only during the filling operationzbut 'also 4during the cp'erati'onof the fceiitrifugai't is po'ssible'to -control the time during which sludge maydischarge throughthe discharge opening IIIA. -This control may beaccomplished by regulating the pressure of the liq- .f

riphery. `Suchopenings'maybey keptclose'dby A I discharge from the separating chamber of the v bowl, inl order to enable the bowl to be modified for different conditions lof work. The channel I1 may ,be arranged in a turntable screw provided with ari" eccentric opening or with exchangeable reguiating discs. l

Instead of discharging the sludge from the bowl through the openings 21, it may be advantageous to recoriduc't it in some way toward the center through channels located outside or in the walls of the bowl. In so doing, a resistance will, of course, be generated', so that the requirements put onjthe: throttled-openings 23 will be reduced. What-we claim is:- f y; I f l. A centrifuge bowlhavin-g a separatingspace and a restricted discharge through the periphery for'sludgda member movable within saidzbowlto open and close said discharge, means'forrning with saily-membera chamber, `said-member` beingv operated by liquid pressure within said chamber, a restricted outlet from'said chamber .to -thefexterior of said centrifuge bowl, and achannelfoon"-l i necting' said Achamber with the sludge space of said bowl, the means forming with said movable memberthe said chamber being a wa-ll of;` the bowl and the said movable member being a plate vslidable parallel with the axis of `the bowlfand thearea of'which exposed to the pressureqwithin said chamber is greater than the area'zexposed to the pressure of-theliquid'in the ,separating space ofthe bowl.` I I vi,

2'. Al centrifugal :bowl having :a restricted `outlet through the periphery forl separated sludgema member movable parallel with-the 'axis rof the bowl in opposite directions to open' and close -said outlet and having on one face an area exposedyto pressurewithin the separatingspace of the vbowl,

:means forming with said member a chamber, said member 'on its other face'bein'g exposed tozprese sure 'within said chamber, thet means forming with said member the said chamberbeingawa-il of" the bowl theface of the member exposed to pressure'in the chamber being of greater diameter and of greater `area than'the area of 'the face of themember'exposed to pressure in the vsepa'- r'at'ing space', said chamber having a restricted outlet v.for separated lliquid l to the exterior ofi' the bowl, achannel connecting said vchair'iber with the sludge space of fthe bowl at a shorter distance than said 'slud'geo'utletfrom'the bowls axis: and through which separated liquid is adaptedl to ini terr'iii'ttently how into said chamber vto thereby in- `to c lose andv open said discharge and enclosing between it and one end of the bcwlthe bowls l separating space and enclosing between it and the other end of the bowl a liquid pressurechamber, there being a restricted outletfromsaid chamber to the exterior of the bowl and a channel connecting the sludge space of the bowl with said chamber, the maximum diameter of the wall of said member exposed to pressure within said chamber exceeding the diameter of the entrance to said discharge and thus exceeding the diameter of its wall exposed to the pressure within said` separating space, the area of said member exposed to pressure within said chamber exceeding the area exposed to the pressure of the liquid in the separating space of the bowl, so that during flow of liquid through said channel into said chamber the liquid pressure in said chamber will exceed the liquid pressure in said separating space and be effective to move and hold said member toward the rst named end of the bowl and thus maintain said sludge discharge closed, while accumulation of sludge adequate to substantially cl'ose the flow of liquid through said channel will, due to the escape of liquid from said chamber through said restricted opening and consequent drop in liquid pressure therein, render the pressure in the separatingspace of the bowl `effec- `tive to move said member, toward the second named end of the bowl and thus open the sludge discharge.

4. A centrifugal separator for separating sludge from liquid, comprising a centrifugal bowl having openings for discharge of sludge and for discharge of purified liquid respectively, a slide member within the bowl and forming one wall of the bowls separating space and movable axially to open and close communication between the per ripheral part of the sludge space of the said sepal rating space and said sludge discharge, said slide member forming between it and a part of the bowl wall a chamber, the area of the wall of said slide member exposed to pressure within said chamber being greater than the area of the wall of said slide member exposed to pressure within the separating space of the bowl, said chamber having a 4restricted outlet, a channel connecting` `said chamber with the inner part of the said sludge space and adapted to purify liquid in its passage-therethrough and convey it to said chamber and thereby exert a liquid pressure therein eiective to move said slide member into position to close the sludge discharge, said channel adapted to be closed by accumulation of sludge in said sludge space to thereby shut off inow of liquid to said chamber, thereby reducing the pressure therein and rendering the pressure of liquid in the separating space effective to move said slide member into position to open said sludge discharge until after suflicient sludge is discharged to allow. resumption of ow `of purified liquid through said channel into said chamber.

5. In a centrifuge bowl having a separating space and a discharge for sludge therefrom, a

A-single member having an area exposed to the pressure within said separating space and which is movable within said bowl to open and close said discharge, means forming with said member a chamber, said member being operated by liquid pressure within said chamber and having an area exposed to pressure within said chamber which is greater than the area exposed to pressure within said separating space, a restricted discharge opening from said vchamber to the exterior of said centrifuge bowl, a channel connecting said chamber with the sludge space of said bowl, and

` means forming a separate conduit leading to said chamber from outside said centrifuge bowl foi,

the admission of operating liquid to said chamber.

pressure within said chamber and having anarea exposed to-pressure within said chamber which is greater than the area exposed to pressure within said separating space, a restricted discharge opening from said chamber to the exterior of said centrifuge bowl, a channel connecting said chamber with the sludge space of said bowl, means forming a separate conduit leading to said chamber from outside said centrifuge bowl for the admission of operating liquid to said chamber, a valve controlling said last named conduit, and means for operating said valve in response to movements of said movable member.

'7. A centrifugal bowl having a separating space and a restricted outlet `through the periphery for sludge, a single member movable within said bowl to open and close said sludge discharge, means forming with said member a chamber, said member having a larger area exposed to pressure within the chamber and a smaller member exposed to pressure within said separating space said chamber having a restricted peripheral outlet, discs within the bowl providing a channel through which separated sludgefree liquid flows inward toward the axis of the bowl and thence into said chamber and thereby creates a liquid pressure therein adequate to move and hold said member into position to close the sludge discharge, accumulationsof sludge being adapted to close the outer ends of the discs against free flow of liquid through said channel, thereby so reducing the liquid pressure in said chamber tha-t the pressure of liquid in the sepa- Y rating space of the bowl will move said member into position to open the sludge discharge.

8. In a centrifugal bowl, a member axially mov.. able back and forth within the bowl and forming between it and one end of the bowl a separating space and forming between it and the other end of the bowl a narrow chamber adapted to receive separated liquid as hereinafter specied, said bowl having a peripheral restricted sludge outlet from said separating space, said axially movable` member being adapted in its back and forth movement to open and close said sludge outlet and having one face of relatively small area exposed to pressure in the separating space and `another face of relatively large area exposed to pressure in said chamber, a channel through which separated liquid can now from the separating space to said chamber when there is relatively little` separated vsludge in the separating space and closable by accumulation of a predetermined thickness of separated sludge in the separating space to thereby stop said flow, therev being in said chamber a restricted opening for discharge of liquid` flowing thereinto; whereby the excess pressure in said chamber, when separated liquid is owing thereinto, moves said I member into position to close said sludge outlet and whereby the pressure in the separating space, after admission of separated liquid into said chamber `is stopped by accumulation of sludge,

moves said member into position to open said sludge outlet.

HANS OLOFLINDGREN. HENRIC THYLEFORS. 

